Malaria is not a problem in the developed world, especially in wealthy countries. But, in poor and under-developed nations, malaria remains a scourge, with 212 million cases and 429,000 deaths in 2016, according to the World Health Organization (WHO). Ninety percent of cases are in sub-Saharan Africa and 70% involve children under 5 years of age. Dr. Karp and his BMGF colleagues are seeking to “bend the curve” from a potential increase to eradication.
Goals include the elimination of the plasmodium parasite from humans, the establishment of complete cure in the hotspots, and ceasing the transmission from mosquito-to-human and vice-versa. The latter focuses on “choke points” such as blocking the path of the parasite to the liver, which occurs within hours of mosquito-human contact. Development of a “rational vaccinology” approach using identified Plasmodia
surface epitopes is already underway. Other strategies include genetically subverting the inheritance of genes that drive the infection and rendering female mosquitoes sterile using the Wolbachia
bacterium. The bacterial approach has been successful in proof-of-concept studies in blocking the transmission of dengue and Zika viruses by mosquitoes.
David Thomas, MD, Johns Hopkins Medicine, Baltimore, MD, discussed the eradication of hepatitis C virus (HCV). HCV is a frustrating disease. It can be eradicated but only by changing the application of medical care and overcoming the societal levels of indifference to a disease that typically afflicts those who are less fortunate and challenged by abuse issues.
“You can go out and find every HCV-infected individual,” asserted Dr. Thomas. Detection of HCV antibody, RNA, or core antigen can be done now using rapid point-of-care tests. The infection can be halted by stopping viral replication. “This is an incredibly weak virus. It replicates only in the cytoplasm of hepatocytes and has no nuclear reservoir so it has to replicate continuously. If you stop replication you eradicate infection,” said Dr. Thomas. Indeed, a 12-week oral regimen of sofosbuvir and velpatasvir works.
If HCV could be eradicated in humans, the infection would forever be done, since we are the only host for it. And here is where the problem lies. HCV is an under-treated disease. In resource-poor settings, the main source of infection has always been and still is, unsafe medically-supervised injections. In resource-rich countries, illicit injection drug use is the main driver, with young (20 to 29 years of age), white, non-urban males being driving the recent 3-fold increase in the prevalence of HCV since 2010 in the United States.
Addressing HCV will require a shift from the current system—where someone is treated when they come to a medical clinic—to a public health approach where disease prevention in the community setting is the norm. This approach has worked elsewhere, most notably Iceland.
The current medically-oriented approach will not keep pace with the increasing number of cases of HCV. In the current reality, eradicating HCV would take hundreds of years. Rather, argues Dr. Thomas, “we need a precision public health approach to eliminate existing HCV infection that includes expanded testing, new models of public care, strengthened public health infrastructure, treatment that is longer acting and lower cost, and prevention strategies.”
“We can eradicate HCV with treatment, [but,] we keep waiting for someone to walk into a clinic. That doesn’t work. We need a public health approach to a public health problem. Finally, we have to overcome the silence surrounding HCV as a world and as a nation,” he opined.
James E. Crowe Jr.: PaxVax: Scientific Advisor , Consulting fee; Takeda: Scientific Advisor , Consulting fee and Research grant; Sanofi: Consultant , Consulting fee , Licensing agreement or royalty and Research grant; Sanofi Pasteur: Investigator , Licensing agreement or royalty; Novavax: Consultant , Consulting fee; Regeneron: Consultant , Consulting fee; Mapp Biopharmaceutical: Investigator , Licensing agreement or royalty; Moderna: Investigator , Grant recipient; Inovio: Collaborator , Research grant; Atreca: Collaborator , Grant recipient
Christopher Karp: none
David Thomas: UpToDate: Editor, Salary; Oxford University Press: Editor, Salary; Merck: Scientific Advisor, Consulting fee
Closing Plenary: 21st Century Cures in Infectious Disease
Monoclonal Antibodies for Infectious Diseases: Why We are on the Threshold of a Major Therapeutic Revolution
James E. Crowe Jr., MD, Vanderbilt University Medical Center, Nashville, TN
Pathogen Eradication: The View Ahead
Christopher Karp, MD, Global Health Discovery & Translational Sciences, Bill & Melinda Gates Foundation, Seattle, WA
The Pivotal Role of Treatment in the Elimination of HCV
David Thomas, MD, MPH, Johns Hopkins University School of Medicine, Baltimore, MD
Brian Hoyle, PhD, is a medical and science writer and editor from Halifax, Nova Scotia, Canada. He has been a full-time freelance writer/editor for over 15 years. Prior to that, he was a research microbiologist and lab manager of a provincial government water testing lab. He can be reached at firstname.lastname@example.org.
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